Electric contact-box



VN0. 6|2,880. Patented Dct. 25, |898.

J. N.,THOMAS & W. M. BROWN.

ELEcTmccoNTAcT sox.

(Applioaton lad 22, 1898.)

(No Modem Fi .23. *g 7 W/ TNE SSE S NTTED STATES PATENT OFFICE.

JOSEPH N. THOMAS AND WILLIAM MILTON BROWN, OF J OHNSTOVN PENNSYLVANIA,ASSIGNORS TO THE JOHNSON COMPANY, OF OHIO.

ELECTRIC CONTACT-BOX.

SPECIFICATION forming part of Letters Patent No. 612,880, dated October25, 1898.

Application led March 22, 1898. Serial No. 674.729. (No model.)

' companying drawings, which form a part of this specification.

Our invention relates to contact-boxes employed with that class ofelectric railways which employ disconnected contact-sections to act asterminals for one side of the circuit, a switching mechanism operated bythe presence of the car being interposed between the feeders connectedwith the said side of the circuit and the said terminal. Such a systemhas been described in a patent issued April 14, 1896, No. 558,151, to W.Milton Brown, and our present invention is particularly applicable tothe general system therein described. Theimprovements, however, in whichour invention consists are also applicable to distinctly differentelectric systems of propulsion. v

Our present invention consists, in part, of improvements upon theelectric contact-box shown and described in the patent of Joseph N.

Thomas, 4issued March 22, 1898, No. 600,937. The various objects of theinvention and the means by which these objects are achieved will be madeto appear more fully hereinafter in describing the construction,combination, and arrangement of the various parts.

Referring to the drawings, Figure l is avertical section on the line 1 1of Fig. 2. Fig. 2 is a plan view of the same with the top or coverremoved. Fig. 3 is a vertical section on the line 3 3 of Fig. 2. Fig. 4is an enlarged sectional view of the upper portion of theswitch-containing vessel. l

The box proper is formed of two principal parts-a non-conducting base 1,preferably of asphaltum,`and a metallic cover 2. The top 2 is secured tothe base 1 by means of hookbolts 3, which are preferably molded into theasphaltum base.

The detailed construction of the cover 2 is not material to our presentinvention. We

have shown it as composed of two sides of iron cast about a center ofbrass or other nonmagnetic material. This construction is one which isadapted for use insystems in which an electromagnet having parallellongitudinal poles is carried by the traveling vehicle, so that thepoles may be over opposite sides of the top, the armature of theswitching mechanism being placed under the center of the top, so as tocomplete the magnetic circuit.

We form the base 1 of the box with an upward projection 1, which iscontinuous around the top of the base and forms a recess in which themetallic cover 2 rests. By this construction the danger of ground-leaksfrom the metallic top to the return-circuit, which usually comprises thetrack-rails, is minimized. At the same time it is not necessary thatasphalt or other material be poured around the box after it is in place.IVe-are therefore enabled to construct the system more cheaply and withgreater celerity and certainty. Another advantage of this arrangement isthat the asphalt projection 1a, where contiguous to the ordinarypavement of the'street, may be at the same level as the same and thengradually inclined upward, thus making the necessary crown of themetallic cover rise less suddenly from the general level of the paving.The advantage of this is obvious.

The contact-box incloses a vessel 4, which we prefer to construct ofporcelain. This vessel contains the mercury 6, which is in connectionwith the supply-feeders by improved means, which we will hereinafterdescribe. In this mercury floats an iron ball 5, whichis the armature ormovable member of the switch. l 7 is preferably a brass tube whichsurrounds the lead-covered cable 8, the latter being connected in anysuitable manner to the supplyfeeders. The end of this cable is securedto a brass pedestal 9, which is molded into a circular insulator 10.This insulator rests upon and is secured to a shelf on abrass vessel 11,fastened upon the end of the tube `7.

12 is a rubber ring which surrounds the lead-covered cable and restsupon the end of IOO the tube 7. The ring 9 also forms a further support,as shown, for the insulator 10.

Some of the functions of the foregoing parts 4will appear more fullyhereinafter. The pedestal 9, insulator 10, and ring 12 are secured tothe end of the cable 7 before the same is placed in position, so thatwhen a cable proves defectiveand a new section must replace it the topof the boX and the vessel, with its switehin g mechanism, are firstremoved,when the defective cable may be drawn upward through the openbase and a new cable with the foregoing parts already attached inserted.The same vessel may now be put back again into the box.

13 is a liquid insulating compound which surrounds vessel 4, pedestal 9,Live. This liquid insulating compound we prefer to form of a mixture ofasphalt and oil, as set forth in a pending application of Bruce Ford,filed January 12, 1898, Serial No. 666,468, in such proportions as tomake a liquid heavier than water, so that any moisture which may enterthe bottom of the box will rise through this compound, and floating onits top be removed from a position of danger.

In the bottom of the vessel 4 is an opening. In this opening restsasteel terminal 14, which is intended to retain the mercury and closethe circuit thereto. The lower part of this terminal is provided with athread which screws into the brass nut 14% This brass nut i is keyed tothe vessel 4 by means of the pin sel 4 to the pedestal 9.

15 and has a female thread which secures it to the pedestal 9. The brassnut 14 therefore forms the medium for securing the ves- This arrangementhas specific advantages in that the mercury cannot escape from thevessel without leaking through several points. It is also a very strongand permanent eonstruction.

In Fig. 4 is shown the improved means which we employin connection withthe passage of the current from the ball 5 (when the ball is raised toits operative position) to the metallic top 2, from which the current isgathered by a traveling collecting device.

According to our present invention we make the porcelain top of thevessel 4 completely closed, except for a small opening through thecenter. Inside the vessel is dovetailed a concave electrode 17,preferably of carbon. This electrode has an annular recess about itstop, into which fits a metallic cap 18, the two being soldered together.Outside the cap is a metallic sheath 19,which bears closely against theupper sides of the vessel, but stands off somewhat from the top, asshown. To the top of the cap 18 is soldered a short conductor 20,whichconductor passes through the beforementioned hole on the top of thevessel and also through the sheath 19 and is soldered to the outsidethereof. Between the inner top of the vessel and the cap 18 is placed arubber bushing 21, which acts as a cushion to protect the porcelainvessel from shock when the ball 5 is raised by magnetic attraction intocontact with the electrode 17. Between the sheath and the outside top ofthe vessel is a small rubber bushing 22,which acts as a cushion toprotect the porcelain vessel from shocks due to traffic over the top ofthe contact-box. The spring 23, secured to the metallic top 2, bearsagainst thetop of the sheath 19 and completes theci rcuit between theelectrode 17 and the metallic top 2. Porcelain or similar materialisvery useful for a vessel of this kind, because of its excellentinsulating character, its imperviousness to moisture, its ability towithstand deterioration, and because of the fact that it will not besoftened by heat. It is, however, more or less brittle and is thereforeapt to break from any sudden shock imparted to it by the rapid movementof the ball 5 or by blows which the top 2 is sure to receive from thehoofs of horses, wheels of vehicles, dive. The arrangement which we haveprovided, however, is very effective in preventing any breakage of thisvessel. Ve have,tirst,the highestinherent strength which a given-sizedporcelain vessel can have, for the top of the vessel is without anysubstantial perforation to weaken it, and, second, the bushings 2l and22 effectually prevent any sudden shock being transmitted to the vessel.

The whole arrangement of our contact-box, as must be obvious from theforegoing description, is such as to reduce the time and` expenserequired for repairs and renewals to the lowest possible point.

We desire to be clearly understood as not limiting ourselves to suchspecific details of construction and arrangement as .might be modiedwithout departing outside the scope of our invention. Such modificationsof these details will readily suggest themselves to those skilled in theart.

Having thus described our invention, what we claim, and desire toprotect by Letters Patent, is-

1. The combination of the closed insulating vessel containing aswitching mechanism, an electrode on each side of the top wall of thesame, a conductor connecting said electrodes, and cushions between eachelectrode and the top of the said vessel.

2. In an electric contact-box, the combination of a sealed vessel ofinsulating material containing the switching mechanism, a fixedelectrode inside the top thereof, a metallicsheath for the top walls ofthe said vessel, and an electric conductor passing through the vesseland connecting the sheath and the said electrode.

3. In an electric contact-box, the combination of a sealed vessel ofinsulating material containing the switching mechanism, an elec- IIOtrede iiXed inside the top thereof, a metallic sulating material, afixed electrode inside the top thereof, a metallic sheath for the topwalls of the Vessel, cushions between the electrode and the Vessel, andbetween the sheath and the Vessel, and an electric conductor passingthrough the top of the vessel and through the cushions, and electricallyconnecting the sheath and electrode.

5. The combination of the sealed Vessel 4,

secured to said nut and in connection with the source of electricsupply.

8. The combination with the Vessel 4 and terminalA 14 therein, of thepedestal 9 connected to one side of the circuit, the nut 1in connectingthe said terminal andpedestahand the locking-pin 15.

9. The tube 7 inclosing feeder 8 and rubber ring 12 surrounding saidfeeder and closing the end of said tube, in combination with open vessel11 containing liquid insulator 13, and the switch containing Vesselsurrounded by said insulator.

' In testimony whereof We have aihxed our signatures in presence of twowitnesses.

JOSEPH N. THOMAS. WILLIAM MILTON BROVN.

Vitnesses: RICHARD EYRE, MYRTLE E. SHARPE.

